The mounting of tubeless tires upon wheels by automobile manufacturers is normally accomplished by high production apparatus wherein a wheel is placed upon a conveyor, the tire is preliminarily positioned relative to the wheel, and as the wheel and tire are conveyed from station to station, the tire may be soaped, the tire forced over the wheel rim and mounted intermediate the wheel rims, the wheel and tire may be rotated relative to each other in accordance with previously applied reference points, and the tire is inflated to a predetermined pressure.
To reduce the duration required for inflation it is common practice to impose an annular axial force upon one of the tire sidewalls which causes the other tire sidewall bead to seat against the associated wheel rim while the deflected sidewall bead is displaced from its wheel rim. Thereupon, an inflation chamber is defined by wheel rim engaging apparatus and compressed air is forced into the tire around the displaced sidewall bead, and upon the desired pressurizing being accomplished the deflected tire sidewall is permitted to expand to seat its bead against the wheel rim to maintain the inflation pressure, and such inflation can be readily accomplished in a very short time.
With high production tire inflation apparatus of the aforementioned type an annular inflation chamber is defined which includes the interior of the tire wherein pressurization of the chamber produces the desired pressure within the tire. To define the inflation chamber an annular wheel seal is usually employed which engages the wheel rim. Further, an annular tire sidewall seal is normally employed which engages the tire sidewall for displacing the sidewall, and also defining the pressurized chamber. The sidewall engaging seal and the wheel rim engaging apparatus are displaceable with respect to each other to produce the desired sequence of operation, but no sealing apparatus is associated with the opposite side of the tire as the seal, which is usually a "lower" seal, is achieved by the engagement of the tire bead with the wheel rim. An example of the aforedescribed tire inflation apparatus is illustrated in assignee's U.S. Pat. No. 4,183,392.
There are several disadvantages inherent in high production tire inflation apparatus as described above. One serious problem occurs at the lower tire bead and wheel rim which are to form a seal during inflation. In order for an effective seal to occur between the nondisplaced tire sidewall bead and the associated wheel rim the bead must fully seat upon the rim. However, due to tire deformation arising from tire banding, temperature, design, or other reasons, an excessive gap or clearance may exist between the uninflated lower tire sidewall bead and rim. Thus, when the apparatus is pressurized considerable air may be lost because of the misfit between tire bead and rim, high noise levels are created due to the escape of large quantities of high pressure air, and if a seal cannot be established the tire will not inflate and must be recycled, and perhaps remounted to produce the required seal necessary for inflation.
Another disadvantage of known tire inflation apparatus results from variations in tire sizes. Most tire inflation apparatus requires that the sizes of the sealing structure for the wheel rim and tire sidewall be changed when different sizes of wheels and tires are inflated, and to change over an inflation line from one tire size to another is time consuming and expensive. Also, there is often a need to "mix" tire sizes on an inflation line, but unless there are only small differences between the sizes the accommodation of different wheel and tire sizes is not readily achieved with conventional apparatus.
Also, in tire inflation apparatus which engage the wheel rim to seal there is the possibility of damaging the rim, particularly in view of the fact that wheels are often formed of aluminum or relatively light gauge steel, and decorative rims are common.
As described above, the majority of tire inflation apparatus wherein the air is introduced into the tire about a displaced sidewall seals the nondisplaced sidewall bead to the tire rim, however, it is known to engage the nondisplaced tire sidewall with a sealing edge or a supporting surface, and such apparatus is shown in U.S. Pat. Nos. 2,595,258; 3,366,153 and in the assignee's U.S. Pat. No. 2,190,117. However, the apparatus shown in these patents is not readily usable with a variety of tire sizes as desired and the inflation apparatus shown in these patents does not overcome many of the problems of the known prior art inflators.
It is an object of the invention to provide high production tire inflation apparatus which is capable of accommodating a wide variety of wheel and tire sizes without modifying the inflation apparatus.
Another object of the invention is to provide tire inflation apparatus of the high production type wherein the wheel is not sealingly engaged during inflation, and both sidewalls of the tire are utilized in the sealing phase during inflation.
Another object of the invention is to provide high production tire inflation apparatus capable of rapidly inflating a tubeless tire wherein both compressed air and pressurized fluid motors are employed in the operation of the apparatus to most effectively translate the inflation components, and resist the pressures imposed upon the apparatus during inflation.
Yet another object of the invention is to provide high production tire inflation apparatus which utilizes an optical sensor to determine the location of a tire sidewall.
An additional object of the invention is to provide a high production tire inflator apparatus wherein the wheel and tire to be inflated are mounted upon a conveyor pallet and the pallet forms a portion of the sealing structure.
In the practice of the invention the tires to be inflated are mounted upon conveyor pallets wherein the tires are indexed between various stations at which the mounting and inflation sequences occur. When the tire and wheel arrive in the inflation apparatus of the invention the tire is located between the wheel rims, and the tire is being supported upon a pallet having a vertical axis. The pallet preferably includes a circular peripheral edge which engages the lower tire sidewall, and this engagement of the pallet and tire sidewall forms a seal during inflation.
The inflation apparatus includes a frame upon which a carriage is vertically positionable by means of a tandem expansible chamber motor system. The motor system includes two coaxial cylinder and piston motors, one motor being operated by compressed air, while the other is operated by pressurized hydraulic fluid, and appropriate controls and valves are utilized with the motors to permit sequential operation thereof. Basically, the air motor is utilized to rapidly lower or raise the carriage and inflation apparatus, while the hydraulic motor is employed to lock the carriage to resist forces imposed upon the carriage by the compressed air during inflation.
The carriage includes an annular tire seal inflation ring head which is lowered into engagement with the upper tire sidewall by the air motor. Upon engagement with the tire sidewall the tire seal will deflect the upper tire sidewall downwardly to produce a clearance between the upper sidewall bead and the upper wheel rim. Such downward pressure imposed upon the tire firmly forces the lower tire sidewall into engagement with the sealing edge defined upon the conveyor pallet, and an inflation chamber is formed by the pallet, tire and seal ring.
The lowering of the seal ring into engagement with the tire occurs under the rapid traverse movement of the compressed air operated motor and a sensing switch engages the wheel rim as the seal ring lowers to sense the size of the wheel and this switch operates the motor controls when sufficient engagement with the tire has occurred to stop the seal ring movement and operate the hydraulic motor which now becomes effective. A compressed air inlet located in the seal ring now permits compressed air to be rapidly introduced into the inflation chamber which quickly produces the desired inflation pressure therein. The upward force imposed upon the seal ring and carriage by the air pressure within the inflated chamber is resisted by the locked hydraulic motor.
After the inflation pressure has been reached the introduction of compressed air into the inflation chamber terminates, and under the control of the hydraulic motor the carriage and seal ring is raised sufficiently to permit the upper tire sidewall bead to seat against the upper wheel rim trapping air within the tire at the desired inflation pressure. Thereupon, air is bled from the seal ring under controlled noise abatement conditions, and upon the seal ring reaching atmospheric pressure the air motor quickly raises the carriage and seal ring from the tire readying the apparatus for the next inflation cycle. The conveyor is indexed and the cycle may then be repeated.
The use of the compressed air motor permits the rapid traverse carriage movement necessary to attain the desired production rate and to achieve such rapid movement with a hydraulic motor system requires high horsepower. The use of the locking hydraulic motor during the inflation cycle permits the high forces imposed upon the seal ring and carriage during inflation to be effectively resisted and very accurate positioning of the seal ring is possible as is necessary when accommodating tires of various sizes.
No contact with the wheel rim exists during the inflation process except for the purpose of sensing the location of the wheel rim. Thus, there is no likelihood of damage to the wheel even though the wheel may be formed of aluminum or relatively light gauge steel, or the rim may be of a decorative type.
The utilization of the pallet as a seal due to the engagement of the pallet edge with the lower tire sidewall simplifies the pallet construction, produces superior sealing with respect to bead and wheel rim sealing, and inflation problems due to deformations existing in the uninflated tire bead due to tire banding, temperatures or other factors are minimized as sealing occurs at both tire sidewalls during inflation. Further, as the apparatus of the invention only requires the positioning of the seal ring on the tire sidewall, and does not require positioning of seal ring structure against the wheel rim, the controls and structure necessary in the practice of the invention are simplified with respect to high production tire inflation apparatus presently being utilized.